Led module assemblies for displays

ABSTRACT

Disclosed is an LED module assembly for a display including a first LED module and a second LED module. The first LED module includes a first unit substrate, a plurality of LED chips mounted on the first unit substrate to form a plurality of pixels, and a first light absorbing layer formed on the first unit substrate. The second LED module includes a second unit substrate, a plurality of LED chips mounted on the second unit substrate to form a plurality of pixels, and a second light absorbing layer formed on the second unit substrate. The first unit substrate and the second unit substrate are laterally connected to each other. Each of the first light absorbing layer and the second light absorbing layer includes a plurality of valleys formed between the plurality of pixels. The first light absorbing layer includes a first inclined portion formed obliquely from the upper end edge of the interface between the first unit substrate and the second unit substrate to the upper portion of the side surface of each of the outer LED chips mounted on the first unit substrate. The second light absorbing layer includes a second inclined portion formed obliquely from the upper end edge of the interface between the first unit substrate and the second unit substrate to the upper portion of the side surface of each of the outer LED chips mounted on the second unit substrate. At least one of the plurality of valleys is formed by the first inclined portion and the second inclined portion meeting each other.

This is a continuation of U.S. application Ser. No. 16/152,380, filedOct. 4, 2018, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to LED module assemblies, and morespecifically to LED module assemblies including LED modules laterallyconnected to one another such that color interference or diffusereflection of light at the seams between the LED modules is prevented,achieving a seamless display.

2. Description of the Related Art

Techniques are already known wherein a plurality of LED modules arelaterally connected to one another to construct an LED module assembly.Such a conventional LED module assembly is applied to an LED display.

FIG. 1 illustrates a conventional LED module assembly including aplurality of LED modules 2 laterally connected to each other. Asillustrated in FIG. 1, each of the plurality of LED modules 2 includes aunit substrate 22, a plurality of LED chips 24 a, 24 b, and 24 c mountedon the unit substrate 22 to form a plurality of pixels, and a blackmolded part 26 formed on the unit substrate 22 to cover the upper andside surfaces of the plurality of LED chips 24 a, 24 b, and 24 c. Theblack molded part 26 can be formed by a transfer molding process using amixture of a resin material and black carbon. The black molded part 26is provided for the purpose of reducing color interference of lightemitted from the side surfaces of the R, G, and B LED chip to achieve apure black display.

The plurality of LED modules 2 are singulated from a larger LED modulestructure. In each of the plurality of LED modules 2, the side surfacesof the unit substrate 22 and the black molded part 26 form cut surfaces.When a display using the LED module assembly is driven, the seamboundaries between the LED modules 2 are made clear, considerablydeteriorating display quality, as shown in FIG. 2. This phenomenoncauses diffuse reflection of light emitted from the plurality of LEDmodules at the cut surfaces of the black molded parts 26 formed by acutting process such as sawing. Transfer molding for the formation ofthe black molded parts 26 requires free spaces for mold pressing.Further, the black molded parts 26 covering the upper portions of theLED chips decrease the amount of light emitted from the LED chips,resulting in poor efficiency. Alternatively, squeezing may be applied tothe formation of the black molded parts 26. However, this process islimited in that it is difficult to maintain the height variation andflatness of the black molded parts.

Further, if the intervals between the seam boundaries created when thecut surfaces are bonded are larger than the intervals between theplurality of LEDs, the seam boundaries look like lines.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above problems, andit is an object of the present invention to provide LED moduleassemblies including LED modules laterally connected to one anotherwherein color interference or diffuse reflection of light at the seamsbetween the LED modules is prevented and the intervals between the seamboundaries are made as small as the intervals between a plurality ofpixels, achieving a seamless display.

An LED module assembly for a display according to one aspect of thepresent invention includes a first LED module and a second LED modulewherein the first LED module includes a first unit substrate, aplurality of LED chips mounted on the first unit substrate to form aplurality of pixels, and a first light absorbing layer formed on thefirst unit substrate; the second LED module includes a second unitsubstrate, a plurality of LED chips mounted on the second unit substrateto form a plurality of pixels, and a second light absorbing layer formedon the second unit substrate; the first unit substrate and the secondunit substrate are laterally connected to each other; each of the firstlight absorbing layer and the second light absorbing layer includes aplurality of valleys formed between the plurality of pixels; the firstlight absorbing layer includes a first inclined portion formed obliquelyfrom the vicinity of the upper end edge of the interface between thefirst unit substrate and the second unit substrate to the upper portionof the side surface of each of the outer LED chips mounted on the firstunit substrate; the second light absorbing layer includes a secondinclined portion formed obliquely from the vicinity of the upper endedge of the interface between the first unit substrate and the secondunit substrate to the upper portion of the side surface of each of theouter LED chips mounted on the second unit substrate; and at least oneof the plurality of valleys is formed by the first inclined portion andthe second inclined portion.

According to one embodiment, each of the light absorbing layers includesvalleys formed between the adjacent LED chips in the plurality ofpixels.

According to one embodiment, the widths of the valleys between thepixels are preferably larger than those of the valleys between thechips.

According to one embodiment, each of the light absorbing layers isformed by applying a liquid or gel-like material including a black colormaterial to the surface of the corresponding substrate.

According to one embodiment, each of the valleys is formed obliquelyfrom the upper end edge of the side surface of the corresponding LEDchip toward the lower end of the valley closest to the surface of thecorresponding substrate.

According to one embodiment, the lower end of each of the valleysbetween the chips is located in the central portion between the twoadjacent LED chips.

According to one embodiment, the LED module assembly includes a lightabsorbing part formed at the interface between the first unit substrateand the second unit substrate.

According to one embodiment, the light absorbing part is formed byspreading a material having a light absorbing color on the side surfaceof the first unit substrate and the side surface of the second unitsubstrate in contact with each other.

According to one embodiment, at least one of the plurality of valleys isformed in contact with a light absorbing pattern film previously formedon the first unit substrate or the second unit substrate.

According to one embodiment, the valleys between the chips are formed incontact with a light absorbing pattern film previously formed on thefirst unit substrate or the second unit substrate.

According to one embodiment, the plurality of LED chips are flip-chipbonded onto the first unit substrate or the second unit substrate.

According to one embodiment, the side surfaces of the first unitsubstrate and the second unit substrate are vertically cut surfaces.

According to one embodiment, the surface of each of the plurality of LEDchips lies at the same level as the upper end of the correspondingvalley and is exposed to the outside.

According to one embodiment, the width of the valley formed by the firstinclined portion and the second inclined portion at the boundary betweenthe first LED module and the second LED module is preferably the same asthe width of the valley formed between the two adjacent pixels on thefirst substrate or the second substrate. An LED module assemblyaccording to another aspect of the present invention includes a firstLED module and a second LED module wherein the first LED module includesa first unit substrate, a plurality of LED chips mounted on the firstunit substrate, and a first light absorbing layer formed on the firstunit substrate; the second LED module includes a second unit substrate,a plurality of LED chips mounted on the second unit substrate, and asecond light absorbing layer formed on the second unit substrate; thefirst unit substrate and the second unit substrate are laterallyconnected to each other; each of the first light absorbing layer and thesecond light absorbing layer includes a plurality of valleys formedbetween the plurality of chips; the first light absorbing layer includesa first inclined portion formed obliquely from the upper end edge of theinterface between the first unit substrate and the second unit substrateto the upper portion of the side surface of each of the outer LED chipsmounted on the first unit substrate; the second light absorbing layerincludes a second inclined portion formed obliquely from the upper endedge of the interface between the first unit substrate and the secondunit substrate to the upper portion of the side surface of each of theouter LED chips mounted on the second unit substrate; and at least oneof the plurality of valleys is formed by the first inclined portion andthe second inclined portion meeting each other.

In the LED module assemblies of the present invention including LEDmodules laterally connected to each other, color interference or diffusereflection of light at the seams between the LED modules is prevented,achieving a seamless display.

More specifically, light absorbing layers are provided in the form ofunderfills and include a plurality of valleys between pixels and aplurality of valleys between chips. A valley between pixels is alsoformed at the seam between the two LED modules to improve seamlesscharacteristics at the seam between the cut surfaces of the LED modulesformed by sawing. This valley is previously formed between cut surfacesby sawing, scribing or breaking to prevent diffuse reflection despitethe formation of the cut surfaces, contributing to an improvement inluminous efficiency. In contrast, an LED module assembly of the priorart suffers from serious diffuse reflection at cut surfaces of blackmolded parts formed by sawing.

In addition, a light absorbing material (for example, one including ablack color material) is not present on the LED chips of the LED moduleassemblies according to the present invention, which is effective inincreasing the amount of light emitted from the LED chips. Furthermore,a height variation is easier to maintain in the LED module assemblies ofthe present invention than in an LED module assembly including blackmolded parts formed by a squeezing process.

Moreover, according to the prior art, defective elements or parts areimpossible to repair or correct after the formation of black moldedparts by squeezing or transfer molding. In contrast, according to thepresent invention, only defective elements or parts can be repaired orcorrected, resulting in high yield and low production cost.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 illustrates an LED module assembly of the prior art;

FIG. 2 shows the problems of the LED module assembly illustrated in FIG.1;

FIG. 3 is a cross-sectional view illustrating an LED module assemblyaccording to one embodiment of the present invention;

FIG. 4 is a plan view illustrating an LED module assembly according toone embodiment of the present invention;

FIG. 5 is an enlarged view of circle “A” of FIG. 3;

FIG. 6 is an enlarged view of circle “B” of FIG. 3; and

FIG. 7 is a view illustrating a further embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention will now be describedwith reference to the accompanying drawings. The drawings and theirdescription are intended to assist in understanding the presentinvention to those skilled in the art. Therefore, the drawings and thedescription should not be construed as limiting the scope of the presentinvention.

FIGS. 3 to 6 illustrate an LED module assembly according to oneembodiment of the present invention.

As illustrated in FIGS. 3 to 6, the LED module assembly includes aplurality of LED modules 100 laterally connected to one another. Theplurality of LED modules 100 include a first LED module 100, a secondLED module, . . . , and an n^(th) LED module. For convenience ofillustration, the first LED module 100 and the second LED module 100adjacent to each other are selected and denoted by the same referencenumeral.

The LED module assembly includes a substrate including a first unitsubstrate 110 as a part of the first LED module 100 and a second unitsubstrate 110 as a part of the second LED module 100. The first LEDmodule 100 and the second LED module 100 are laterally connected to eachother. Thus, the first unit substrate 110 and the second unit substrate110 are also laterally connected to each other. The first LED module 100and the second LED module 100 include a plurality of LED chips 121, 122,and 123 mounted on the first unit substrate 110 and the second unitsubstrate 110 to form a plurality of pixels 120, respectively. The firstLED module 100 and the second LED module 100 include a first lightabsorbing layer 130 formed on the first unit substrate 110 and a secondlight absorbing layer 130 formed on the second unit substrate 110,respectively. The unit substrates 110 may be, for example, selected fromprinted circuit boards (PCBs), flexible substrates (e.g., FBCBs), andtransparent organic substrates.

For example, the light absorbing layers 130 may have a black color forlight absorption. The light absorbing layers provide a pure blackdisplay by other elements of the LED module assembly, which will beexplained in more detail, and remove color interference of light fromthe side surfaces of the LED chips 121, 122, and 123 to improve displayimage quality. Unlike the black molded parts described in theabove-mentioned prior art, the light absorbing layers 130 are not formedon the upper surfaces of the LED chips 121, 122, and 123, causing nosubstantial decrease in the amount of light emitted from the LED chips.Particularly, the light absorbing layers ensure a seamless display whena display using the LED module assembly is driven.

The first LED module 100 and the second LED module 100 can be producedby singulating an LED module structure (not illustrated) including asubstrate (not illustrated) whose size is several times larger thanthose of the unit substrates and a plurality of LED chips mounted on thesubstrate. The side surfaces of the first unit substrate 110 and thesecond unit substrate 110 are vertically cut surfaces. A light absorbingpart 112 is formed at the interface between the vertically cut surfacesof the first unit substrate 110 and the second unit substrate 110. Thelight absorbing part 112 may be formed by spreading a material having alight absorbing color (for example, a black ink) on the side surface ofthe first unit substrate 110 and the side surface of the second unitsubstrate 110.

The plurality of pixels 120 are arrayed in a matrix on each of the firstunit substrate 110 and the second unit substrate 110. The LED chips 121,122, and 123, specifically the red LED chips 121, the green LED chips122, and the blue LED chips 123, are arranged at uniform intervals inthe pixels 120. The LED chips 121, 122, and 123 are flip-chip bondedonto the unit substrates 110, thus eliminating the need to form bondingwires thereon. The LED chips 121, 122, and 123 mounted on the unitsubstrates 110 may be vertical-type LED chips. In this case, bondingwires may be optionally used.

FIG. 4 is a plan view illustrating an LED module assembly according toone embodiment of the present invention. The LED module assemblyincludes a plurality of LED modules 100. In each of the LED modules 100,pixels 120 are arrayed at constant intervals a in the transversedirection and at constant intervals b in the longitudinal direction. Inother words, the intervals a between the pixels 120 adjacent to eachother in the transverse direction are constant and the intervals bbetween the pixels 120 adjacent to each other in the longitudinaldirection are constant. In a state in which the plurality of LED modules100 are connected to one another, the interval a between the two pixelsadjacent to each other in the transverse direction between the two LEDmodules 100 and 100 adjacent to each other in the transverse directionis the same as the intervals a between the pixels in the correspondingLED modules. The interval b between the two pixels adjacent each otherin the longitudinal direction between the two LED modules 100 and 100adjacent to each other in the longitudinal direction is the same as theintervals b between the pixels in the corresponding LED modules.Accordingly, the width of a valley formed between the two adjacent LEDchips 121 and 121, 122 and 122 or 123 and 123 between the two pixelsadjacent to each other in the transverse direction is the sameirrespective of whether the two pixels adjacent to each other in thetransverse direction are in the same LED module or in the different LEDmodules adjacent to each other in the transverse direction. The width ofa valley formed between the two LED chips 121 and 123 adjacent to eachother in the longitudinal direction is the same irrespective of whetherthe two pixels adjacent to each other in the longitudinal direction arein the same LED module or in the different LED modules adjacent to eachother in the longitudinal direction.

Referring again to FIGS. 3 to 6, the first light absorbing layer 130formed on the first unit substrate 110 and the second light absorbinglayer 130 formed on the second unit substrate 110 include a plurality ofvalleys 132 formed between the plurality of pixels 120. Herein, thevalleys 132 are also called “inter-pixel valleys”.

Each of the plurality of valleys 132 is formed between the two adjacentLED chips 123 and 121 between the two adjacent pixels. Each of the lightabsorbing layers includes valleys 133 formed between the adjacent LEDchips 121 and 122 or 122 and 123 in the plurality of pixels 120. Herein,the valleys 132 are also called “inter-chip valleys”

The interval between the two adjacent LED chips 123 and 121 between thetwo adjacent pixels 120 and 120 is larger than the interval between thetwo adjacent LED chips 121 and 122 or 122 and 123 in each pixel 120.Thus, the width of the valley 132 between the two adjacent pixels 120and 120 is determined to be larger than the width of the valley 133formed between the two adjacent LED chips 121 and 122 or 122 and 123 ineach pixel 120.

Each of the inter-pixel valleys 132 is formed obliquely from the upperend edge of the side surface of the outer LED chip 121 or 123 in thecorresponding pixel toward the lower end 132 a of the inter-pixel valleyclosest to the surface of the first unit substrate 110 or the secondunit substrate 110 while being curved slightly. Here, the lower end 132a of each of the inter-pixel valleys 132 a may be located in the centralportion between the two adjacent LED chips 123 and 121 between the twoadjacent pixels 120 and 120. Most preferably, the lower ends 132 a ofthe inter-pixel valleys are substantially in contact with the surface ofthe first unit substrate 110 or the second unit substrate 110.

Each of the inter-chip valleys 133 is formed obliquely from the upperend edge of the side surface of the LED chip 121, 122 or 123 toward thelower end 133 a of the inter-chip valley closest to the surface of thefirst unit substrate 110 or the second unit substrate 110 while beingcurved slightly. Here, the lower end 133 a of each of the inter-chipvalleys 133 a may be located in the central portion between the twoadjacent LED chips 121 and 122 or 122 and 123 in the corresponding pixel120. Most preferably, the lower ends 133 a of the inter-chip valleys aresubstantially in contact with the surface of the first unit substrate110 or the second unit substrate 110.

Here, it is preferable that the inter-pixel valleys 132 are deeper thanthe inter-chip valleys 133.

Particularly, the first light absorbing layer 130 includes a firstinclined portion 134 a formed obliquely from the upper end edge of theinterface between the first unit substrate 110 and the second unitsubstrate 110 to the upper portion of the side surface of each of theouter LED chips 121 or 123 in the pixels on the first unit substrate110. The second light absorbing layer 130 includes a second inclinedportion 134 b formed obliquely from the upper end edge of the interfacebetween the first unit substrate 110 and the second unit substrate 110to the upper portion of the side surface of each of the outer LED chips121 or 123 in the pixels on the second unit substrate 110. The firstinclined portion 134 a and the second inclined portion 134 b aresymmetric to each other with respect to the interface and meet eachother to form the inter-pixel valleys 134. The inter-pixel valleys 134are provided between the first unit substrate 110 and the second unitsubstrate 110 as well as on the first unit substrate 110 and the secondunit substrate 110. Preferably, the inter-pixel valleys 134 defined bythe first inclined portion 134 a of the first light absorbing layer 130and the second inclined portion 134 b of the second light absorbinglayer 130 meeting each other have the same shape and the same size asthe other inter-pixel valleys 134 of the first light absorbing layer 130or the second light absorbing layer 130.

The light absorbing layers 130 can be formed by applying a liquid orgel-like resin material including a black color material to the surfacesof the first unit substrate 110 and the second unit substrate 110. Theresin material may be applied by a spray technique. The valleys 134defined by the first inclined portion 134 a and the second inclinedportion 134 b meeting each other are formed obliquely from the upper endedge of the side surface of the corresponding LED chip toward the lowerend of the valley closest to the surface of the corresponding substrate.The black color material may be, for example, black carbon.

The liquid or gel-like resin material including the black color materialapplied to the first unit substrate 110 and the second unit substrate110 mounted with the plurality of LED chips 121, 122, and 123 by a spraytechnique is filled between the adjacent pixels and between the LEDchips in the pixels to form the light absorbing layers 130.

Nevertheless, the liquid or gel-like resin flows down from the uppersurfaces of the LED chips 121, 122, and 123 along the side surfaces ofthe LED chips 121, 122, and 123 due to its surface tension, with theresult that the upper surfaces of the LED chips 121, 122, and 123 areexposed to the outside. Thus, the upper surfaces of the LED chips 121,122, and 123 lie at the same level as the upper ends of the valleys 132and 133 and are exposed to the outside. Light can be emitted through theupper surfaces of LED chips 121, 122, and 123 on which the lightabsorbing layers are not found, thus preventing the luminous efficiencyof the LED chips from deteriorating.

FIG. 7 illustrates an LED module assembly according to anotherembodiment of the present invention.

Referring to FIG. 7, the LED module assembly includes a substrate, morespecifically a first or second unit substrate 110. A light absorbingpattern film 115 is formed on the upper surface of the substrate. Thelight absorbing pattern film 115 is previously formed such that itcovers the exposed surface of the substrate 110 except electrodepatterns connected to electrode pads of LED chips 121, 122, and 123. Thelight absorbing pattern film 115 may be a black photo solder resist(PSR) or a black tape. As in the previous embodiment, a light absorbinglayer 130 includes an inter-pixel valley 132 located between the twoadjacent LED chips 123 and 121 between two adjacent pixels on the firstunit substrate 110 or the second unit substrate 110, an inter-chipvalley 133 located between the two LED chips 121 and 122 or 122 and 123in each of the pixels on the first unit substrate 110 or the second unitsubstrate 110, and another inter-pixel valley 134 (see FIG. 3) locatedbetween the two adjacent LED chips 123 and 121 between the two adjacentpixels between the first unit substrate 110 and the second unitsubstrate 110. The inter-pixel valleys and inter-chip valley are formedin contact with the light absorbing pattern film 115 at the lower endsthereof. This construction can previously eliminate the possibility thatthe surfaces of the unit substrates may be exposed through the openlower ends of the valleys and can achieve a uniform black colorthroughout the LED module assembly.

What is claimed is:
 1. An LED module assembly for a display comprising aplurality of LED modules comprising a first LED module and a second LEDmodule, wherein the first LED module comprises: a first unit substrate;a plurality of pixels, each of which comprises at least three LED chipsmounted on the first unit substrate; and a light absorbing layer formedon the first unit substrate and comprising a plurality of valleys, eachof which is formed between the two adjacent LED chips in thecorresponding pixel on the first unit substrate, and a plurality ofvalleys formed at constant intervals between the pixels adjacent to eachother in the transverse direction and at constant intervals between thepixels adjacent to each other in the longitudinal direction, wherein thesecond LED module comprises: a second unit substrate connected to thefirst unit substrate while being in contact with one side surface of thefirst unit substrate; a plurality of pixels, each of which comprises atleast three LED chips mounted on the second unit substrate; and a lightabsorbing layer formed on the second unit substrate and comprising aplurality of valleys, each of which is formed between the two adjacentLED chips in the corresponding pixel on the second unit substrate, and aplurality of valleys formed at constant intervals between the pixelsadjacent to each other in the transverse direction and at constantintervals between the pixels adjacent to each other in the longitudinaldirection, and wherein the widths of the valleys between the pixels arelarger than those of the valleys between the chips.
 2. The LED moduleassembly according to claim 1, wherein the light absorbing layerscomprise a plurality of valleys formed between the plurality of pixelsand at least one of the plurality of valleys is formed by a firstinclined portion and a second inclined portion.
 3. The LED moduleassembly according to claim 1, wherein the valleys between the pixelsare deeper than the valleys between the chips.
 4. The LED moduleassembly according to claim 1, wherein each of the valleys between thechips is formed from the upper end edge of the side surface of thecorresponding LED chip and forms its lower end with the surface of thefirst unit substrate or the second unit substrate.
 5. The LED moduleassembly according to claim 4, wherein the lower end of each of thevalleys between the chips is located in the central portion between thetwo adjacent LED chips in the corresponding pixel and is curved.
 6. TheLED module assembly according to claim 1, wherein a light absorbing partis formed at the interface between the first unit substrate and thesecond unit substrate.
 7. The LED module assembly according to claim 1,wherein the at least three LED chips are flip-chip bonded onto the firstunit substrate or the second unit substrate.
 8. The LED module assemblyaccording to claim 1, wherein the side surfaces of the plurality of unitsubstrates comprising the first unit substrate and the second unitsubstrate are vertically cut surfaces.
 9. The LED module assemblyaccording to claim 1, wherein the surface of each of the at least threeLED chips is exposed to the outside and lies at the same level as theupper end of the corresponding valley.
 10. An LED module assembly for adisplay comprising a plurality of LED modules comprising a first LEDmodule and a second LED module, wherein the first LED module comprises:a first unit substrate; a plurality of pixels, each of which comprisesat least three LED chips mounted on the first unit substrate; and alight absorbing layer formed on the first unit substrate and comprisinga plurality of valleys, each of which is formed between the two adjacentLED chips in the corresponding pixel on the first unit substrate, and aplurality of valleys formed at constant intervals between the pixelsadjacent to each other in the transverse direction and at constantintervals between the pixels adjacent to each other in the longitudinaldirection, wherein the second LED module comprises: a second unitsubstrate in contact with and connected to the first unit substrate; aplurality of pixels, each of which comprises at least three LED chipsmounted on the second unit substrate; and a light absorbing layer formedon the second unit substrate and comprising a plurality of valleys, eachof which is formed between the two adjacent LED chips in thecorresponding pixel on the second unit substrate, and a plurality ofvalleys formed at constant intervals between the pixels adjacent to eachother in the transverse direction and at constant intervals between thepixels adjacent to each other in the longitudinal direction, and whereinthe intervals in the longitudinal or transverse direction at theinterface between the first unit substrate and the second unit substrateare the same as the intervals in the longitudinal or transversedirection in the first unit substrate or the second unit substrate. 11.The LED module assembly according to claim 10, wherein the plurality oflight absorbing layers comprise a plurality of valleys formed at theintervals in the longitudinal or transverse direction and at least oneof the plurality of valleys comprises a first inclined portion and asecond inclined portion.
 12. The LED module assembly according to claim10, wherein the plurality of light absorbing layers comprise a pluralityof valleys formed at the intervals in the longitudinal or transversedirection and a first inclined portion and/or a second inclined portionare formed between the outer ones of the pixels located on the pluralityof unit substrates in the longitudinal or transverse direction.
 13. TheLED module assembly according to claim 10, wherein the valleys betweenthe pixels are formed by a first inclined portion and a second inclinedportion symmetric to each other with respect to the interface betweenthe first unit substrate and the second unit substrate at the boundarybetween the first LED module and the second LED module.
 14. The LEDmodule assembly according to claim 10, wherein the valleys between thepixels are deeper than the valleys between the chips.
 15. The LED moduleassembly according to claim 10, wherein each of the valleys between thechips is formed from the upper end edge of the side surface of thecorresponding LED chip and forms its lower end with the surface of thefirst unit substrate or the second unit substrate.
 16. The LED moduleassembly according to claim 15, wherein the lower end of each of thevalleys between the chips is located in the central portion between thetwo adjacent LED chips in the corresponding pixel and is curved.
 17. TheLED module assembly according to claim 10, wherein a light absorbingpart is formed at the interface between the first unit substrate and thesecond unit substrate.
 18. The LED module assembly according to claim10, wherein the at least three LED chips are flip-chip bonded onto thefirst unit substrate or the second unit substrate.
 19. The LED moduleassembly according to claim 10, wherein the side surfaces of theplurality of unit substrates comprising the first unit substrate and thesecond unit substrate are vertically cut surfaces.
 20. The LED moduleassembly according to claim 10, wherein the surface of each of the atleast three LED chips is exposed to the outside and lies at the samelevel as the upper end of the corresponding valley.